Re: row filtering for logical replication

From: Greg Nancarrow <gregn4422(at)gmail(dot)com>
To: Ajin Cherian <itsajin(at)gmail(dot)com>
Cc: Dilip Kumar <dilipbalaut(at)gmail(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Euler Taveira <euler(at)eulerto(dot)com>, Peter Smith <smithpb2250(at)gmail(dot)com>, Rahila Syed <rahilasyed90(at)gmail(dot)com>, Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com>, Önder Kalacı <onderkalaci(at)gmail(dot)com>, japin <japinli(at)hotmail(dot)com>, Michael Paquier <michael(at)paquier(dot)xyz>, David Steele <david(at)pgmasters(dot)net>, Craig Ringer <craig(at)2ndquadrant(dot)com>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, Amit Langote <amitlangote09(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: row filtering for logical replication
Date: 2021-10-15 04:30:37
Message-ID: CAJcOf-eG9nQoYMdz5asBm5_JuKdQV+i7pv5PCxUqGU_K887x4w@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On Wed, Oct 13, 2021 at 10:00 PM Ajin Cherian <itsajin(at)gmail(dot)com> wrote:
>
> I have made the change to use the virtual slot for expression
> evaluation and avoided tuple deformation.
>

I started looking at the v32-0006 patch and have some initial comments.
Shouldn't old_slot, new_slot and tmp_new_slot be cached in the
RelationSyncEntry, similar to scantuple?
Currently, these slots are always getting newly allocated each call to
pgoutput_row_filter_update() - and also, seemingly never deallocated.
We previously found that allocating slots each time for each row
filtered (over 1000s of rows) had a huge performance overhead.
As an example, scantuple was originally newly allocated each row
filtered, and to filter 1,000,000 rows in a test case it was taking 40
seconds. Caching the allocation in RelationSyncEntry reduced it down
to about 5 seconds.

Regards,
Greg Nancarrow
Fujitsu Australia

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Kyotaro Horiguchi 2021-10-15 06:00:57 Re: Inconsistency in startup process's MyBackendId and procsignal array registration with ProcSignalInit()
Previous Message Shinya Kato 2021-10-15 04:29:12 Re: [PATCH] Added TRANSFORM FOR for COMMENT tab completion